As means of advertising a merchandise or a company, an advertising light 1, as shown in FIG. 9, is widely used, consisting of a plurality of lamps with different colors to be lighted on and off. But its structure can be considered to have the following disadvantages.
1. It generally has not a small number of lamps or tubes, to resultant high cost for power energy, complicated assemblage and labor and time waste.
2. The control system for the lamps or tubes is so complicated that its cost cannot be low and, not economical.
Next, a conventional traffic light always has at least three lamps for one side indication and six lamps for both side indication. In case four traffic lights are accomodated at a cross road as shown in FIG. 10, 24 lamps are needed in total. Then it leads to high cost and difficult complexity in its structure and wiring. In addition, conventional traffic lights lack a time indicating device to show the length of time a lamp of red, green or yellow color to be lighted, so drivers may easily run into an accident by guessing changing time of traffic lights to drive their cars. Conventional traffic lights can be considered to have the following disadvantages.
1. They, either of one side or both side indication, are so complicated in fixing and wiring structure and color changing, liable to give baffling impression to passers-by and drivers, and has low economic gain owing to their high cost.
2. They have only a simple function to show go-or-stop sign by changing alternately the three lamps of three separate colors, without any other indications for drivers and walkers.
3. They have a large number of lamps using large amounts of electricity.
As for a headlight and a fog light used in common cars, they are seperate and independent from each other to be used on different occasions, having respectively four lamps requiring rather complicated wiring.